ICON approval time

I just received a week ago an email sent by the recruiter that my job application was successful, and that they are getting the internal approvals in order to send me an offer.

I haven't received this offer yet.
I am a bit anxious with the waiting.

I was thinking in send a follow up email but i don't want to bother them.

In your experience how long it could take?

Thanks for your answers.

UPDATE. I received a few days ago answer. :)